This renewal R01 application builds on our productive research on the epidemiology of substance use disorders (SUDs). By capitalizing on multiple waves of data from the National Survey on Drug Use and Health (NSDUH), we have published a series of epidemiological papers related to the use or abuse of alcohol, cigarettes, inhalants, marijuana, cocaine, heroin, stimulants, opioids, and hallucinogens/MDMA, as well as the factors associated with the utilization of substance abuse treatment services. In light of the lack of research on the empirical classification of individual and comorbid SUDs in adolescents for the emerging DSM-V, this application utilizes our solid knowledge of the NSDUH as a foundation and expands our research efforts on substance use and disorders to investigate previously unaddressed questions regarding measurement bias and latent constructs of DSM-IV diagnostic criteria used to generate national estimates of DSM-IV SUDs. This application seeks to address Crosscutting Issues recommended by PA-08-124 Epidemiology of Drug Abuse by applying both epidemiological and several latent variable modeling approaches to analyze the already collected wealth of diagnostic data and to shed new light on the quality of diagnostic assessments and diagnostic classification of SUDs in adolescents aged 12-17 years. Study aims are to: (1) determine the extent of co-occurrences of dependence symptoms with abuse across 10 substance classes;(2) evaluate the dimensionality and item-level psychometric properties of the criteria for each SUD;(3) investigate item-response bias (measurement error) in the assessment of SUDs;(4) evaluate dimensional, categorical, and integrated dimensional and categorical approaches to the classification of specific SUDs;(5) examine external validator variables of empirically defined diagnostic subgroups for each SUD;and (6) identify empirically defined comorbid SUD subtypes using new diagnostic classifying approaches and evaluate external validator variables of empirically defined comorbid SUD subtypes. PUBLIC HEALTH RELEVANCE: The ongoing National Survey on Drug Use and Health serves as the primary source for documenting national statistics for substance use disorders. Findings from this proposed study will make a very timely and high-influence contribution to the field by elucidating the quality or measurement bias of diagnostic criteria used to generate national estimates of substance use disorders in adolescents and by providing new findings relevant to an empirical base of substance use disorder classification for the emerging DSM-V and ICD-11.